#define _CRT_SECURE_NO_WARNINGS 1
#include<stdio.h>
int main()
{
	int arr[10];
	int  sum = 0;
	int num = 0;
	double pingjun = 0;
	for (int i = 0; i < 10; i++)
	{
		num = 0;
		scanf("%d",& arr[i]);
		num = arr[i];
		sum += num;
	}
	pingjun = sum / 10.0;
	printf("%lf", pingjun);

	return 0;

}